The FreeRTOS kernel is now an MIT licensed AWS open source project, and these pages are being updated accordingly.

Quality RTOS & Embedded Software

About Contact Support FAQ Download

Menu

Quick Start

Supported MCUs

PDF Books

Trace Tools

Ecosystem

Quick Start Guide

Support Forum

⇓ Download Source ⇓

FreeRTOS+ Ecosystem

FreeRTOS+TCP:
Thread safe TCP/IP stack

SafeRTOS:
TUV certified RTOS

OpenRTOS:
Commercial Licensed RTOS

Fail Safe File System:
Ensures data integrity

FreeRTOS BSPs:
3rd party driver packages

Trace & Visualisation:
Tracealyzer for FreeRTOS

CLI:
Command line interface

WolfSSL SSL / TLS:
Networking security protocols

RTOS Training:
Delivered online or on-site

IO:
read(), write(), ioctl() interface

FreeRTOS+ Lab Projects

FreeRTOS+POSIX:
POSIX threading API

FreeRTOS+FAT:
Thread aware file system

crDELAY
[Co-Routine Specific]

croutine.h


void crDELAY( CoRoutineHandle_t xHandle, 
              TickType_t xTicksToDelay )

crDELAY is a macro. The data types in the prototype above are shown for reference only.

Delay a co-routine for a fixed period of time.

crDELAY can only be called from the co-routine function itself - not from within a function called by the co-routine function. This is because co-routines do not maintain their own stack.

Parameters:

xHandle	The handle of the co-routine to delay. This is the xHandle parameter of the co-routine function.
xTickToDelay	The number of ticks that the co-routine should delay for. The actual amount of time this equates to is defined by configTICK_RATE_HZ (set in FreeRTOSConfig.h). The constant portTICK_PERIOD_MS can be used to convert ticks to milliseconds.

Example usage:


 // Co-routine to be created.
 void vACoRoutine( CoRoutineHandle_t xHandle, 
 UBaseType_t uxIndex )
 {
 // Variables in co-routines must be declared static if they must maintain 
 // value across a blocking call. This may not be necessary for const 
 // variables. We are to delay for 200ms.
 static const xTickType xDelayTime = 200 / portTICK_PERIOD_MS;

     // Must start every co-routine with a call to crSTART();
     crSTART( xHandle );

     for( ;; )
     {
        // Delay for 200ms.
        crDELAY( xHandle, xDelayTime );

        // Do something here.
     }

     // Must end every co-routine with a call to crEND();
     crEND();
 }